Also there is the psychological factor of the staff member watching the ipad screen the entire time, and looking at it again immediately after you are done. Lik

Also there is the psychological factor of the staff member watching the ipad screen the entire time, and looking at it again immediately after you are done. Like are you going to put zero and have them think "Fuck you cheap asshole" or are you going to be guilt tripped into throwing $3 away that the staff member might not even see? It taps into the same moral dilemma as a beggar accosting you on the street.